Mixture Of Ethanol Research Articles

Preparation of pyridinium-based ionic liquid and application as a green catalyst for the synthetic route of 4H-1-benzopyran-5(6H)-ones

1-(4-sulfobutyl)pyridinium chlorozincate ionic liquid was synthesised in high yield (89%) through a simple route and characterised using FT-IR, NMR, and HRMS spectroscopy. The one-pot reaction was employed for the condensation reaction of benzaldehydes, 5,5-dimethyl-1,3-cyclohexanedione, and dicyanomethane, utilising the prepared ionic liquid catalyst. The optimal conditions for the reaction were achieved with a catalyst loading of 10 mol%, a solvent mixture of water and ethanol (1:1, v/v), maintained at 100°C for 180 minutes. A broad spectrum of benzopyran-5(6H)-one derivatives was prepared, yielding moderate to good results. The notable features of this procedure include readily available substrates, short reaction times, the use of environmentally friendly solvents, and the elimination of the need for chromatography in the isolation of products. Anew acidic pyridinium-based ionic liquid was successfully synthesised and used as a catalyst in the synthetic process of 2-amino-3-cyano-4-phenyl-7,7-dimethyl-7,8-dihydro-4H-1-benzopyran-5(6H)-ones. These reactions involved a condensation reaction of aromatic benzaldehydes, 5,5-dimethyl-1,3-cyclohexanedione, and dicyanomethane in a solvent mixture of ethanol and water, resulting in the desired products in moderate to good yields. The procedure is efficient and eco-friendly, and the products can be easily obtained by recrystallisation. Thus, this protocol offers an alternative to existing methods.

Viscosity measurement and correlation for dense fluid mixture of carbon dioxide and ethanol at 313–343 K and 15–30 MPa

The viscosity ηm of dense fluid mixtures of carbon dioxide and ethanol was determined from the pressure drop between the inlet and outlet of a packed bed using the Ergun equation at temperatures from 313.2 K to 343.2 K and pressures from 15 MPa to 30 MPa over the entire range of ethanol composition. The ηm values for the fluid mixtures decreased with increasing temperature and increased with increasing pressure under isocratic conditions. In addition, the values measured ηm with Ergun eq. were correlated with the equation combining the Eyring theory and the perturbed chain statistical associating fluid theory equation of state (PC-SAFT EoS) and with that based on the rough hard-sphere (RHS) model proposed by Dymond and Assael. The accuracies of the Eyring + PC-SAFT EoS and the RHS model were 8.7% and 12%, respectively, in terms of average relative deviation for 80 conditions over the entire range of ethanol composition.

Enriched supercapacitive performance of electrochemically tailored β-Co(OH)2/CoOOH nanodiscs from sacrificial Co3(PO4)2·4H2O microbelts

Electrochemically induced structural reconstruction process of metal precursors into their corresponding metal hydroxides/(oxy)hydroxides is developed as an ingenious strategy towards preparing efficient electrode material. However, the influence of electrochemical activation on the charge storage ability of electrode material is barely explored. Herein, we have utilized a synthetic strategy (solvothermal reaction in water:ethanol mixture) to prepare Co3(PO4)2·4H2O microbelts and subsequently applied the electrochemical bulk reconstruction process in 1 M KOH electrolyte. A thorough physical and electrochemical characterization unveil that the electrode material is converted into redox active site rich β-Co(OH)2/CoOOH nanodiscs via etching of lattice anionic PO43− moieties. The material possesses a specific capacitance of 386 F g−1at a current density of 0.25 A g−1. Additionally, a hybrid device constructed with β-Co(OH)2/CoOOH nanodiscs and activated charcoal (AC) as positive and negative electrodes has achieved a high energy density of 13.33 Wh Kg−1at a power density of 400 W kg−1. Further, the device displayed a good capacitance retention of 93 % (columbic efficiency ~98 %) up to 10,000 cycles. The improved charge storage of reconstructed material with abundant redox active sites could be attributed to the facile diffusion of electrolyte ions into the bulk of the material.

Airborne Ouzo: Evaporation-induced emulsification and phase separation dynamics of ternary droplets in acoustic levitation

We experimentally investigated the evaporation dynamics of acoustically levitated Ouzo droplets (a mixture of ethanol, water, and anise oil). Acoustic levitation has gained significant attention in various fields owing to its potential to create a lab-in-a-drop. Although evaporation is a key process in nature and industry, many studies have focused on single and binary components, and ternary droplets in acoustic levitation have rarely been experimentally investigated. In this study, the evaporation-induced spontaneous emulsification (the Ouzo effect) and phase separation process at 40–90 vol. % ethanol were visualized. We estimated the concentration change by evaporation of each component in the levitated ternary droplets based on an evaporation model to determine the experimental results. Our experimental results revealed four distinct stages of evaporation in levitated Ouzo droplets: (1) preferential evaporation of the volatile component (ethanol), (2) spontaneous emulsification (myriad micro-oil droplets generation), (3) phase separation forming a core–shell droplet, and (4) water evaporation completion resulting in the remaining oil droplets. Finally, we analyzed the emulsification process using a spacetime diagram. These findings suggest that acoustic levitation is suitable for physicochemical manipulation in mid-air.

Electrochemical Analysis for Total Alkalinity of Water by the Measurement of Cathodic Prepeak of Quinone Caused by Surplus Acid.

In this study, an electrochemical analysis, coupled with the concept of back neutralization titration and the voltammetric determination of surplus acid, is proposed for determining the total alkalinity of water samples. When linear sweep voltammetry of 3,5-di-tert-butyl-1,2-benzoquinone (DBBQ) with H2SO4 in a water and ethanol (44 : 56, v/v) mixture was carried out using a bare glassy carbon working electrode, a cathodic prepeak of DBBQ caused by H2SO4 was observed on the voltammogram at a more positive potential than when compared with the original cathodic peak of DBBQ. When similar voltammetry was carried out in the presence of Na2CO3 and H2SO4, the cathodic prepeak height of DBBQ was decreased with an increase in the Na2CO3 concentration. The decrease of the cathodic prepeak height of DBBQ was found to be linearly related to the Na2CO3 concentration ranging from 0.025 to 2.5 mM (r2 = 0.998). The total equivalent concentrations of inorganic bases in samples of mineral water and tap water were determined, and then the results were converted to the total alkalinities of the water samples (mg/L CaCO3). The total alkalinities of the water samples determined by the present electrochemical analysis were essentially the same compared with those by the neutralization titration method. From these results, we were able to demonstrate that the present electrochemical analysis with accuracy and precision could be applied to determine the total alkalinity, which is one of the indicators to examine water quality. The present electrochemical analysis would contribute to achieving the sustainable development goals (SDGs) of #6 and #14.

Optimizing Extract Preparation from Laurel (Laurus nobilis L.) Leaves Using a Pulsed Electric Field

This study explores the bioactive compound extraction from laurel (Laurus nobilis L.) leaves using a pulsed electric field (PEF) as a standalone extraction technique. The primary parameters impacting the extraction process were optimized through response surface methodology. Specifically, solvent composition (ethanol and water mixtures) and liquid-to-solid ratio, along with other key PEF conditions (i.e., electric field intensity, pulse period, and pulse length) were examined. The antioxidant capacity was evaluated through DPPH and FRAP assays, whereas total polyphenol content was also measured. A comparison was also made between the extracts produced with and without PEF. The results showed that after 30 min of extraction, the best parameters were a pulse period of 355 μs, a pulse duration of 55 μs, and an electric field intensity of 0.6 kV/cm. A liquid-to-solid ratio of 10 mL/g was chosen, whereas the best solvent was determined to be 25% (v/v) ethanol/water mixture. The PEF-treated extract contained 77% more polyphenols compared to the untreated sample. In addition, PEF-treated samples had a rise of up to 288% for certain individual polyphenols. Correlation analyses also revealed interesting trends among bioactive compounds and the antioxidant capacity of the extracts. The effect of the investigated parameters on polyphenol recovery was demonstrated, indicating that comparable investigations should consider these parameters to optimize polyphenol extraction yield. Regarding green and non-thermal standalone techniques, PEF outshines other extraction techniques as it could also be used as a sustainable way to swiftly generate health-promoting extracts from medicinal plants.

Tunable Colloidal Properties of Lauramidopropyl Betaine and Li Co-modified Montmorillonite in Ethanol/Water.

Montmorillonite (Mt) is a hydrophilic clay mineral with a generally high cationic exchange capacity and a remarkable swellability in water. Yet the application of Mt in cosmetics, paints, polymer nanocomposites, drug delivery systems, and tissue engineering are limited due to its unfavorable swelling and dispersion in alcohol/water mixtures. Improving the swellability and dispersibility of Mt in mixtures of ethanol and water remains challenging. Here, we showed that the swellability and dispersibility of Mt in ethanol/water could be significantly enhanced when lithium-Mt (Li-Mt) was intercalated by zwitterionic surfactant lauramidopropyl betaine (LPB). The binding mechanism of the LPB intercalate to Li-Mt originated from a combination of van der Waals forces, ion-dipole interaction, and electrostatic attraction. Due to the synergistic effect of Li+ and LPB, the comodified Mt (LPB-Li-Mt) exhibited excellent swellability, dispersibility, and rheological properties. The structure, morphology, zeta potential, dispersibility, and gel-forming performance of LPB-Li-Mt can be modulated by the concentrations of ethanol in ethanol/water mixtures. When the ethanol concentration increased to 75% v/v ethanol solution, the free swelling of LPB-Li-Mt remained above 80%. The results from X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray photoemission spectrometry, and small-angle X-ray scattering confirmed the full exfoliation of LPB-Li-Mt at 75% (v/v) ethanol solution. The formation of a stable colloidal LPB-Li-Mt dispersion in a mixture of ethanol/water might be derived from the association between water molecules and the Li+, the hydrophobic interaction, and the ion-dipole of ethanol with the LPB molecules. The findings provide a guide for improving dispersion and swelling of Mt and modified ones in water-miscible organic solvents.

Particulate filtration by cryogenic condensation using a high efficiency Stairmand cyclone separator

This paper describes the synergy of a high-efficiency Stairmand cyclonic separator and the phenomenon of condensation generated by the low temperatures of the mixture of liquid nitrogen and ethanol, to increase the separation efficiency on particles with diameters of 1 μm, 45 μm, 75 μm, 150 μm and 250 μm. The cyclone separator adds the phenomenon of condensation, generating a film of liquid water on its internal walls. The film of liquid water causes a loss of kinetic energy in the particles, reducing their speed and becoming stuck. Al2O3 particles and pozzolana rock particles are used to perform the particle separation experimental tests. A computational fluid dynamics analysis using the second order RSM model is incorporated to describe the fluid dynamic behavior of the particles within the separator cyclone. The results in computational fluid dynamics show the agglomeration of larger diameter particles near the internal walls. Using condensation as a phase change generated by cryogenic mixing results in an overall particle separation efficiency of 76.00 %, standing for an increment of 70.14 % in comparison to a conventional high-efficiency Stairmand separator cyclone.Technological innovation: Particles, filtration, separation, condensation, cryogenic.

Separation of 4-substituted 5-methylpiracetam stereoisomers on polysaccharide-based chiral stationary phases

Monitoring of stereoisomer content in samples containing chiral compounds with multiple chiral centers is an important and challenging task in chiral liquid chromatography. 4-Phenyl-5-methylpiracetam, containing two chiral centers, was used as model compound to explore the stereorecognition ability of polysaccharide-based chiral selectors. Initially, the chromatographic behavior of racemic 4-phenyl-5-methylpiracetam on nineteen commercially available polysaccharide-based chiral columns was tested with a mobile phase, consisting of a mixture of ethanol and n-hexane. The obtained results were analysed, and nine chiral phases were selected for further investigation of seven newly synthesized 4-substituted 5-methylpiracetam chiral separations. Our subsequent studies showed that chiral stationary phases based on amylose tris(5-chloro-2-methylphenylcarbamate) and amylose tris[(S)-α-methylbenzylcarbamate] posess higher ability for chiral recognition of stereoisomers of the studied analytes.

Solid phase microextraction of rhodamine B in cosmetic samples using ZnS@GO@WMCNTs Nanocomposite with Spectrophotometric Detection

Rhodamine B dye (RhB) has carcinogenicity, genotoxicity, neurotoxicity and toxicity on living cells and therefore its use is prohibited. but it is still secretly used in cosmetics and foods. For this reason, it is important to develop analytical methods for accurate and sensitive analysis of trace levels of RhB dye in cosmetic and food samples. In this study, a new solid phase microextraction method (SPME) was developed for quick and cheap analysis of RhB in cosmetic samples. A new nanohybrid material including graphene oxide (GO), multi-walled carbon nanotubes (MWCNTs) and zinc sulfide nanopartices (ZnS) was synthesized by hydrothermal synthesis method and the new ZnS@GO@WMCNTs nanohybrid material was used as sorbent in simultaneous separation and preconcentration of RhB from cosmetic products by SPME. ZnS@GO@WMCNTs material was characterized by Raman spectroscopy, scanning electron microscopy (SEM), SEM-Mapping and energy dispersive X-Ray fluorescence (EDX) techniques. The effects of experimental parameters such as amount of sorbent, pH of sample solution, sample volume, effects of matrix, eluent solutions on the recoveries of RhB were investigated. RhB dye adsorbed on ZnS@GO@WMCNTs was eluted with acetic acid–ethanol mixture (2:1) and determined by using UV–Visible spectrophotometer at 550 nm. The fact that RhB adsorbed quantitatively on the adsorbent at all pH values shows that strong Van der Waals interactions between the ZnS@GO@WMCNTs and RhB molecules are effective in adsorption. In optimal experimental conditions, the limit of detection (LOD) and preconcentration factor (PF) of the proposed MSPE-UV/Vis spectroscopy procedure were 4.74 and 44, respectively. The MSPE-UV/Vis procedure was successfully applied to the microextraction and determination of RhB in nail polishs ve lipstick samples with recoveries in the range 95–101 %.

Optimization and scale up of production of the PSMA imaging agent [18F]AlF-P16-093 on a custom automated radiosynthesis platform

BackgroundRecent advancements in positron emission tomograph (PET) using prostate specific membrane antigen (PSMA)-targeted radiopharmaceuticals have changed the standard of care for prostate cancer patients by providing more accurate information during staging of primary and recurrent disease. [68Ga]Ga-P16-093 is a new PSMA-PET radiopharmaceutical that demonstrated superior imaging performance in recent head-to-head studies with [68Ga]Ga-PSMA-11. To improve the availability of this new PSMA PET imaging agent, [18F]AlF-P16-093 was developed. The 18F-analog [18F]AlF-P16-093 has been synthesized manually at low activity levels using [18F]AlF2+ and validated in pre-clinical models. This work reports the optimization of the production of > 15 GBq of [18F]AlF-P16-093 using a custom automated synthesis platform.ResultsThe sensitivity of the radiochemical yield of [18F]AlF-P16-093 to reaction parameters of time, temperature and reagent amounts was investigated using a custom automated system. The automated system is a low-cost, cassette-based system designed for 1-pot syntheses with flow-controlled solid phase extraction (SPE) workup and is based on the Raspberry Pi Zero 2 microcomputer/Python3 ecosystem. The optimized none-decay-corrected yield was 52 ± 4% (N = 3; 17.5 ± 2.2 GBq) with a molar activity of 109 ± 14 GBq/µmole and a radiochemical purity of 98.6 ± 0.6%. Run time was 30 min. A two-step sequence was used: SPE-purified [18F]F− was reacted with 80 nmoles of freeze-dried AlCl3·6H2O at 65 °C for 5 min followed by reaction with 160 nmoles of P16-093 ligand at 40 °C for 4 min in a 1:1 mixture of ethanol:0.5 M pH 4.5 NaOAc buffer. The mixture was purified by SPE (> 97% recovery). The final product formulation (5 mM pH 7 phosphate buffer with saline) exhibited a rate of decline in radiochemical purity of ~ 1.4%/h which was slowed to ~ 0.4%/h when stored at 4 °C.ConclusionThe optimized method using a custom automated system enabled the efficient (> 50% none-decay-corrected yield) production of [18F]AlF-P16-093 with high radiochemical purity (> 95%). The method and automation system are simple and robust, facilitating further clinical studies with [18F]AlF-P16-093.

Sustainable and white HPLC method for simultaneous determination of amlodipine and atorvastatin in film-coated tablet

This study presents a collaboration between academia and the pharmaceutical industry with one goal, to implement the transformation of the conventional into sustainable HPLC methods and to use these methods in the routine quality control of medicines. Therefore, a sustainable, fast, and robust high-performance liquid chromatography (HPLC) method for the determination of amlodipine (AML) and atorvastatin (ATV) in film-coated tablets was developed. The chromatographic separation was performed on stable bond C8 column (150 × 4.6 mm, 5 μm), using a mixture of ethanol and 0.02 M sodium dihydrogen phosphate monohydrate, pH 3.0 (63:37%, v/v) as a mobile phase. The optimized conditions enabled the determination of AML and ATV within 5 min, providing satisfactory results for system suitability parameters. The method was validated in accordance with the ICH guideline in terms of specificity, linearity, accuracy, and precision (repeatability and intermediate precision). The robustness of the method was confirmed using the Plackett-Burman experimental design. The greenness features of the method were assessed using the Eco-scale index, the AMGS calculator, and the AGREE tool. The high value of the whiteness score (93.5) confirmed that the method meets the requirements for the three main pillars (analytical, ecological, and economical) for the sustainable method development. The method was applied for the determination of both analytes in pharmaceutical dosage form (film-coated tablets that contains 10 mg AML and 10 mg ATV).

Structural characterization of a new samarium–sodium heterometallic coordination polymer

Lanthanide-containing materials are of interest in the field of crystal engineering because of their unique properties and distinct structure types. In this context, a new samarium–sodium heterometallic coordination polymer, poly[tetrakis(μ2-2-formyl-6-methoxyphenolato)samarium(III)sodium(I)], {[SmNa(C8H7O3)4]·solvent} n (Sm-1), was synthesized and crystallized via slow evaporation from a mixture of ethanol and acetonitrile. The compound features alternating SmIII and NaI ions, which are linked by ortho-vanillin (o-vanillin) ligands to form a mono-periodic chain-like coordination polymer. The chains propagate along the [001] direction. Residual electron density of disordered solvent molecules in the void space could not be reasonably modeled, thus the SQUEEZE function was applied. The structural, vibrational, and optical properties are reported.

Optimization of Pulsed Electric Field-Based Extraction of Bioactive Compounds from Cannabis sativa Leaves

The current investigation examines the application of pulsed electric fields (PEFs) for isolating polyphenols from Cannabis sativa var. Futura 75 leaves. Firstly, the solvent composition, which included ethanol, water, and various mixtures of the two, was explored, along with the liquid-to-solid ratio. Subsequently, the primary parameters associated with PEFs (namely, pulse duration, pulse period, electric field intensity, and treatment duration) were optimized. The extracted samples were analyzed to determine their total polyphenol content (TPC), and individual polyphenols were also evaluated through high-performance liquid chromatography. In addition, the antioxidant activity of the extracts was assessed through ferric-reducing antioxidant power (FRAP) and DPPH assays. The extracts prepared utilizing PEFs were compared to the extracts obtained without PEFs in terms of their TPC, FRAP values, and DPPH activity. The results indicate that the most effective extraction parameters were a pulse duration of 10 μs, a pulse period of 1000 μs, and an electric field strength of 0.9 kV/cm after 25 min of extraction. The most efficient solvent was determined to be a 50% (v/v) mixture of ethanol and water in a 20:1 liquid-to-solid ratio. The extract obtained under the optimal conditions exhibited a ~75% increase in TPC compared to the extract obtained without any application of PEFs, while some individual polyphenols exhibited an increase of up to ~300%. Furthermore, significant increases of ~74% and ~71% were observed in FRAP and DPPH assays. From the information provided, it was observed that the tested variables had an impact on the recovery of polyphenols from C. sativa leaves.

Vinyl-ester nanocomposites based on a binary-solvent system for well-exfoliated graphene and enhanced performance

This paper introduces a green approach for preparing well-dispersed graphene nanoplates (GNPs) in vinyl-ester (VE) resin. The GNPs were exfoliated in a novel binary-solvent system comprised of a water and ethanol mixture (S nanocomposites). Water and ethanol were considered poor solvents for graphene, but a combination of them could be an ideal solvent mixture. TEM images of the S nanocomposites revealed well-exfoliated graphene sheets with a few wrinkles. Hence, the effective surface areas of the GNPs considerably increased, playing a vital role in enhancing the performance of the nanocomposites. With the incorporation of just 0.4 wt% of exfoliated GNPs (S2 nanocomposite) in the VE, the tensile strength, and toughness enhanced by 51%, and 63%, respectively. Fractography analysis indicated smooth fracture surfaces of pure resin changed to very rough surface structures for the S2 nanocomposite. The viscoelastic properties of the specimens indicated that directly loading GNPs into the resin decreased the glass transition temperature (Tg) of the VE resin. In contrast, the samples prepared by liquid-phase exfoliation enhanced the Tg of the VE. Lastly, the barrier properties of the S2 nanocomposite revealed that its water absorption decreased by 26% compared to the pure resin.

A Multidisciplinary Approach toward CMOS Capacitive Sensor Array for Droplet Analysis.

This paper introduces an innovative method for the analysis of alcohol-water droplets on a CMOS capacitive sensor, leveraging the controlled thermal behavior of the droplets. Using this sensing method, the capacitive sensor measures the total time of evaporation (ToE), which can be influenced by the droplet volume, temperature, and chemical composition. We explored this sensing method by introducing binary mixtures of water and ethanol or methanol across a range of concentrations (0-100%, with 10% increments). The experimental results indicate that while the capacitive sensor is effective in measuring both the total ToE and dielectric properties, a higher dynamic range and resolution are observed in the former. Additionally, an array of sensing electrodes successfully monitors the droplet-sensor surface interaction. However practical considerations such as the creation of parasitic capacitance due to mismatch, arise from the large sensing area in the proposed capacitive sensors and other similar devices. In this paper, we discuss this non-ideality and propose a solution. Also, this paper showcases the benefits of utilizing a CMOS capacitive sensing method for accurately measuring ToE.

Elimination of detached Listeria monocytogenes from the biofilm on stainless steel surfaces during milk and cheese processing using natural plant extracts

Bacterial cells can form biofilm on food contact surfaces, becoming a source of food contamination with profound health implications. The current study aimed to determine some Egyptian medicinal plants antibacterial and antibiofilm effects against foodborne bacterial strains in milk plants. Results indicated that four ethanolic plant extracts, Cinnamon (Cinnamomum verum), Chamomile (Matricaria chamomilla), Marigold (Calendula officinalis), and Sage (Salvia officinalis), had antibacterial (12.0–26.5 mm of inhibition zone diameter) and antibiofilm (10–99%) activities against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella Typhimurium. The tested extracts had minimum inhibitory concentration values between 0.14 and 2.50 mg/ml and minimum bactericidal concentration values between 0.14 and 12.50 mg/ml. L. monocytogenes was more sensitive for all tested ethanolic extracts; Sage and Cinnamon showed a bacteriocidal effect, while Chamomile and Marigold were bacteriostatic. The ethanolic extracts mixture from Chamomile, Sage, and Cinnamon was chosen for its antibiofilm activity against L. monocytogenes using L-optimal mixture design. Gas chromatography and mass spectrometry analysis showed that this mixture contained 12 chemical compounds, where 2-Propenal,3-phenyl- had the maximum area % (34.82%). At concentrations up to 500 µg/ml, it had no cytotoxicity in the normal Vero cell line, and the IC50 value was 671.76 ± 9.03 µg/ml. Also, this mixture showed the most significant antibacterial effect against detached L. monocytogenes cells from formed biofilm in stainless steel milk tanks. At the same time, white soft cheese fortified with this mixture was significantly accepted overall for the panelist (92.2 ± 2.7) than other cheese samples, including the control group.

Valorization of Monoraphidium sp. microalgal biomass for human nutrition applications

The green microalga Monoraphidium sp. has potential for biodiesel production since it grows fast and can accumulate high levels of lipids. However, there is a lack of information on the potential use in human nutrition. In this work Monoraphidium sp. was characterized in terms of macronutrients with a special focus on the fatty acid profile of the lipid fraction and on the amino acid profile of the proteins. Furthermore, aiming at nutrient valorization, various methods for lipid extraction that could be used in the production of high quality and safe foods were investigated. To this end, the focus was on cell disruption methods in order to optimize oil recovery. The Monoraphidium sp. biomass had a high protein concentration (44.5 %) and a relatively low lipid concentration (12.5 %) but was rich in ω-3 fatty acids demonstrating its high nutritive value. Regarding cell disruption, ultrasonication and high-speed homogenization were insufficient to disrupt cells under the conditions examined. On the other hand, the effectiveness of the ball milling was regulated via processing time and water-to-biomass ratio and complete cell disruption could be achieved by this method. For lipid extraction, solvent extraction using a mixture of food-grade hexane and ethanol resulted in an oil recovery of 70.4 %, whereas using ethanol alone as an environmentally friendly solvent resulted in an oil recovery equal to 54 %. Supercritical CO2 extraction resulted in a lower oil recovery (25 %), whereas ethanol addition, as a cosolvent to CO2, significantly increased the oil recovery (60 %).

Use of an Ethanol-powered Motor-generator to Electricity Generation for Countryside Population and Small Isolated Communities

Due to the growing demand in the global energy mix and the constant concern about the use and the scarci ty of fossil fuels, the study of cleaner, cheaper, easy obtaining and environment-friendly alternative fuels has become a matter of general interest. In Brazil, the sugar cane-based ethanol is a good alternative for the use of gasoline, since the country has a land fit for cultivation of this crop, skilled labor and suitable climatic conditions, and has low emissions of greenhouse gases. In this study it was used a four-cylinder Otto-cycle engine powered by gasoline with no adjustments. It was evaluated the system performance, power, voltage, and specific fuel consump tion using mixtures of gasoline and ethanol in the follow ing proportions: E0, E5, E10, E15, E20, E30, E35, E40, E45, E50, E55, E60, E65, E70, E75, E80, E85, E90, E95 e E100. The amount of harmful exhaust gases expelled by the engine (CO2 and NOx), was also analyzed, and it was observed a reduction in the amount of CO2 expelled by the engine due to the increase of ethanol concentration in the mixture. In contrast, the amount of NOx increased due to the fact that the temperature in the combustion chamber is higher for ethanol. As a result it was observed that the motor-generator provides 800 W of power, which is enough to allow the operation of refrigerator, television and electric bulbs in a small home.

Emissions of Pollutant Gases (CO and CO<sub>2</sub> ) when Using Fuel Mixtures (Ethanol-Petrol) in Internal Combustion Engines

The objective of the study is to evaluate the emissions of pollutant gases (CO and CO2) when using fuel mixtures (ethanol-petrol) in internal combustion engines. The experiments were carried out in the Engine Laboratory of the Faculty of Engineering Sciences of Agrarian University of Havana (AUH) using JACTO engine. To obtain the amount of toxic gases emitted into the atmosphere (CO2 and CO), the balance of the combustion equations was proposed for the different mixtures estimated taking into account the established coefficients of excess air. The analysis of the combustion process based on 10, 20 and 30 percent ethanol mixtures with hydration (80%; 85%; 90 %; 95%) and conventional petrol of category B-85 for rich mixtures (α = 0,85) and for lean mixtures (α = 1,15) showed that CO2 and CO emissions to the atmosphere are reduced to 17% for considered mixtures as compared to petrol. Despite higher relative fuel consumption as compared to petrol, there is a significant positive environmental effect.